Blackboard.



L. L. GI'IIBBLL.

BLACKBOARD.

APPLICATION FILED AIJGJ. I9Is.

Patented Aug. 21, 1917.

Unirrnn srarrns rarnnr oFF/ion.

' LELAH LGRIBBLE, or MniTERAL ronv'r,y WISCONSIN.

BLACKBOARD.

To all fwwmjt may concern.'

Be it known that I, LELA-H L. GRIBBLE, a

i' `citizen of the United States, and resident of Mineral Point, inthe county of Iowa and State of Visc'onsim'have invented new and I i ence being'hadlto the accompanying drawings, which. are a part of thislspecication. y

'The invention relates to blackboards.

The invention is more particularly .de-v Y signed to provide a blackboard vinthe form t of a. roll whichmay be moved by the teacher v to display thefdaily lessons so that each days lesson may be 4printed or written on the roll and the roll moved to position by Lend of the roller 6 and serves as a guide the teacher when anyv particular lesson is desired, the roll being moved -by the teacher rthrough a crankwhich is alwaysl turned in l the same direction. Y *Y l Y lThe invention is further designed to provide a driving mechanism forthe-blackboard o roller 5.

roll in whichV the crankis always turned in clutch connection witlrthe crank."A

The invention further consists inthelsev'- eral features hereinafter set forth and more particularly defined by claims atthe conclusion hereof.

In the drawings:

Figure 1 is a front view of the vdeviceiemj.`

bodying the invention;

Fig. -2 is a section taken l ori-the line 2-2 of Fig. l;

e Fig. 3 is a section takenonthe line 3--3 of Fig. 2. I

The device comprises a blackboard roll l mounted on upper and lower rollers 5 and 6 respectively, means for supporting each of said rollers, and Ymeans for operating the rollers to move the roll 4 into the desired position.

The upper roller 5 is of usual construction and is provided at one end with a circular guide plate 7 and the lower roller 6 is provided with a similar plate 8. The means for supporting the upper roller 5 comprises a pair of brackets 9 and 10 which are adapted to be secured to any suitable support as the wall 11 shown in Fig. 2 and in which pins 12 and 13 are pivotally mounted, said pins also being secured to the ends ofthe A driving pulley 14 is interposed between the.V end of the roller 5 and the Specification of Letters Patent. Patented A11g.21, 1917. ,t application mea August 7317916. serial Nb. 113,466. y y

bracket 10 and secured to the end of the said roller to yform a guide similar to the guide plate 7. V t 4 The means for supporting the lower roller 6 comprises uprights 16 and 17 to which the lower roller is pivotally secured. At the end of the roller l6 adjacent the plate 8 the said roller is pivotallyA secured to the'upright 16by a pin 18 journaled in said upright. The roller Gis pivotally secured to the upright 17 by means of a slidable and revoluble crank shaft 19 which is Ournaled in a bearingv 20 at the upper 7end 0f the upright 17 and provided with a handle19. A

tudinally. movable crank 19 adjacent to one move the roll 4 into the desired position comprises thepulleys 14 and 21, a driving connection between said pulleys consisting of a. cross-belt 22 and a driving connection between the crank 19 `with the pulley 21 or with the lower roller 6.

t This driving connection between the crank 19 and the pulley 21 andthe roller 6 consists ofa clutch for either locking the pulley 21 to the crank 19 or the lower roller 6 to the crank 19. 'This clutch consists of a .spring clutch member 23 secured to the inner end of the crank 19 and mounted in a end 25 which is adapted to engage notches 21 in the pulley 21 to lock the pulley to said crank or to engage roller 6. The means for locking the lower roller 6 to the crank 19 consists of the clutch 23 with the projecting finger 25 which is adapted to be moved into engagement with either of two oppositely disposed notches 26 in the end of the roller 6 when said crank is moved inwardly within the bore 27 in the end of the roller 6. In order that the clutch 23 may be held in engagement with either the pulley 21 or the roller 6 means are provided for preventing end-wise movement of the crank 19 with respect to the upright 17. This means consists of a spring pressed nger 28 which projects downwardly through an aperture 29 in the bearing 20 and is adapted to engage with either of a pair of grooves 3-0 and 31 formed in the crank 19 at the ends of a spherical portion 32 formed in the shaft 19. The spherical portion 32 permitsthe shaft 19 to be moved either in# 5 Win' through the pulley 21, heit 22 and pulley' 1K4: yberotated in a'countei'-"'c'lock-wise dit-eenen to' wndu'the roll 4 upoh the upper i roller `until the operator hasfreached the de- 'sired part 'of the boardwhich he wishes to` display tothe pu1`oil`sV fojr the lesson of the day. When it is desired to move the roll 4 downwardly the crank V194 is zpushed inwardly-anni theJ enger 2'8 engages inv the groeve 31, the Spherical portion 32 of thev b crank 19 permitting the movement of the finger 2e 'friom they groote e0v art-aint@ the;v :groove 31. Under these conditions the sjring pressed clutch 23 is moved inwardly and engages with one ,of the notches 26 in the roll and on a clockfwise rotation4 of the crankd), which it will be observed is the saine direction as is required to move the vroll upwardly', the lower rolleris rotated in a clock-wise direction Yand the roll l is moved downwardly andbwoundup on the' lower roll to display the desired lesson.

l will thus be', apparent that the 4driving mechanism for thev roll permits said roll to be moved upwardly ory downwardly upon' its" carrying rollers while the operating' cranlr is always krotated `inthe saine direction.

Theinventionthus exemplifies a simple andeiiicient construction of blackboard roll which is Weir aaapted for thepurphse desired,

What I lclaim as my inventionis:

1. In a device of the character described, the combination of a blackboard roll, upper and lower supporting rollers for said roll, aipulley carried by the upper roll, a revoluble shaftslidably mountedy in the lower roller, a pulley loosely mounted on said shaft, a crossbelt connecting said loose pulley with the `pulley carried by the upper roller, said loose pulley and lower roller having notches therein, said-'shaft having a recess therein', a spring pressed finger mounted in the recess in said shaft and adapted to engage the notch .in saidloose pulley or the notch in said roller to connect the shaft in driving relation therewith, and means for securing said shaft against' endwise f movement when it is connected to either said loose pulley or said lower roller.

2. In a device of the character described, the combinationofa blackboard roll, upper and lower supporting' rollers for 'saidroll,

a pulley carried by the Yupper' roller, a revoluble cranked shaft slidably mounted in the lower roller, a supporting bearing for said shaft, a pulley loosely mounted on said shaft, a cross-belt connecting said loose pulley with the pulley carried by lthe upper; roller, said loose` pulley.y and, lower roller having notches therein, said shaft having a recess therein, a spring pressed nnger mounted in the recess Vin said shaft and adapted to` engage the notch in said loose pulley or the notcht in said roller to connect the shaft in driving relation therewith, said shaft having annular grooves therein and a spherical portion between said grooves, and means for' securing'said shaft different lateral positions comprising a spring pressed pin mounted in said supporting' bearing and adapted to seatV in either of said annular gfOVS. l y

In testimony whereof@ afIiX my signature.

' LELH L: GRIBBLE. 

